Sigma Star Saga is a hybrid Shoot 'em Up / RPG developed by WayForward Technologies and published by Namco for the Game Boy Advance in 2005.An alien race known as the Krill attacked Earth 60 years ago, and, though they were driven off, the global ecosystem was left in tatters due to a "hole the size of Canada" getting carved out of the Pacific Ocean. Now, the Krill have returned, and humanity is ready for vengeance. You play as Ace Pilot Ian Recker, who, after leading the initial counterattack, is sent undercover in the Krill army to gather intelligence on a rumored superweapon they're developing. However, the lines between friend and foe quickly become blurred, and Recker is left in serious confusion as to where his loyalty truly belongs as he tries to unravel the mysteries of the Krill.Out of battle, you walk around areas like in any typical RPG, but during random encounters, you enter a side-scrolling shmup battle. You're able to customize your ship's weapon using three different types of Gun Data chips, which are found in overworld areas. Cannon chips determine how your ship fires bullets (i.e. straight forward, spreading, aimed manually, rapid fire). Bullet chips determine what kind of projectiles you shoot (basic, long-range shots, lasers, wavy shots, rockets, etc.). Impact chips determine what your shots do when they hit enemies (nothing, create lasting explosions, turn around, burst into flames, etc.). One chip of each type is used to create a unique combination. With the total number of chips of each type, you can make exactly 15,680 different guns. However, you can only use one unique gun at a time, because you can only switch Gun Data outside of battle.
This game provides examples of:
Ace Pilot: Recker, as previously mentioned, as well as Psyme.
Bad Boss: Commander Zelly seems to have a reputation amongst the Krill leadership for this sort of behavior, at one point stated to be worse than the guy everyone calls the Tyrannical Overlord. She shows it when she slaughters her entire base personnel in order to keep sensitive information from being leaked... even though 90% of them had no idea that this sensitive information even existed. It's subverted in the endgame, where Zelly is just about the only high-ranking ally the player has.
Bizarre Alien Biology/Sexual Dimorphism: played for all it's worth. Apparently, the females are telepathic, and grow wings when they're in love. Said wings are detachable, and are given to the person she likes.
Boss Rush: Actually, it's more of a mini-boss rush, if such a thing exists.
Breast Plate: Female parasites seem more to protect their host's modesty than anything else (although, given their Bizarre Alien Biology, the upper chest and nether regions may very well be the only places female Krill are vulnerable).
"So do your slug bikini thing."
Cardboard Obstacle: Quite a few, actually. Lots of backtracking is required to get past most of them, and largely subverted by the scanner, which allows you to find most of the game's (hidden) equipment.
One of the straight examples of a cardboard obstacle is also more symbolic in nature rather than a result of poor design. The commander's room in Starbase 6 is accessible only via an item which you should already have, but the person inside gives some meaning to the method used to get in.
Character Level: During shoot-em-up battles, the enemies you kill leave behind experience orbs (which could be mistaken for suicide bullets, since they're basically tiny dots). Gathering enough of these boosts your maximum health. Interestingly, it is your character's (living) armor that gathers the experience, not the character himself.
Earth All Along: Most of the game is spent searching for a series of six planets which will ultimately lead to a Doomsday Device. Earth is the "seventh" planet, which had said device gouged out of it.
Earth-Shattering Kaboom: Sort of. The Sleeping Flesh uses entire planets as eggs, so when they "hatch"... Ironically, part of what the Krill were doing in their first "attack" on Earth was saving it from this fate. Sort of.
Floating Continent: Every planet seems to consist entirely of these (except, presumably, Earth).
Gambit Pileup: Keeping up with the plot in the latter half of the game can be somewhat difficult, to say the least.
Game-Breaking Bug: Protip: don't shoot the "tombstone" enemies on the Forgotten Planet as your last kill of the battle. This occasionally makes the battle Unwinnable, since no more enemies spawn, but the battle doesn't end.
It's also a very bad idea to level up any time during the boss fight stage there, again for the same reason.
Giant Space Flea from Nowhere: Although most of the game's bosses tie in pretty well with the story, it does throw a couple of these at you (including a literal swarm of giant space fleas).
One of which (a giant flying skeleton) is Lampshaded hilariously by Scarlet when Recker tries to tell her about it:
"Way to go fantasy nerd (sic). Did you find the +1 Dagger, too?"
Gladiator Games: Early in the game, you are forced to fight another Krill soldier. Luckily, they let you keep your gun.
A God Am I: The Tyrannical Overlord when he merges with the Flesh Deity.
Hopeless War: The Krill military outnumbers humanity's by a very large margin. Subverted in that the Krill don't even consider themselves at war with Earth. Earth's entire military is seen as so pathetically small that it isn't even worth fighting. The two "attacks" they made? They were ridding Earth of an extremely destructive Cosmic Horror type thing, and later simply checking up on us to see how well the Earth was recovering. Earth mistook them for attacks and retaliated, "like frightened animals who bite back after blood is drawn", as one Krill puts it.
Locked in a Room: Recker and Psyme are sent to the Ice Planet inside a cargo box.
Love Triangle: Recker, Psyme, and Scarlet. Psyme wins in both endings where she survives, Scarlet wins if she survives and Psyme dies.
Luck-Based Mission: Some random encounters are outright unwinnable if you are unlucky enough to be summoned by a large/slow moving spaceship in a constricted area that it cannot possibly navigate through without crashing (at least one such area results in a crash before the game even relinquishes control of the ship to you). And since there's no option to retreat, your only option when faced with any fight that you have no chance of winning is to commit suicide.
Mercy Invincibility: Notable as the game not only provides this normally, but there is also a power-up which provides it for every 30 hits you make. Can be something of a game breaker when combined with a gun that can score hits fast enough to keep it going near-constantly.
Missing Secret: sort of. The inventory code was for some reason copied over from the gun data code, resulting in about a gazillion more slots than you will ever be able to fill. May or may not count as a Missing Secret, but is definitely a case of lazy programming.
Mistaken for Pregnant: One particularly hilarious subplot partway through the game has Recker thinking this about Psyme, mainly due to an incomplete understanding of Krill physiology. To be fair to him, though, the comments made by the Krill characters hinted that something "miraculous" was taking place...
Multiple Endings: There are four different endings to the game... which one you see depends on which main characters you keep alive.
New Game+: After beating the game, it can be replayed with all previously unlocked weapons and ships available at the beginning... as well as get a chance to get the best ending, which is unavailable on the first playthough.
Not So Different: By way of a Meaningful Name to note the similarity between the two, your human CO, Tierney, and the Tyrannical Overlord. Both are willing to sacrifice anybody and anything, even their own species, to get control of the bioweapon.
Ominous Save Prompt: the game gives you a somewhat-unneeded one of these (as you would probably have remembered to save before heading into the battle in question, anyways).
One-Hit-Point Wonder: Subverted, although you only receive Mercy Invincibility if you crash into something.
One-Man Army: There are two instances in wich Recker wipe out the crew of a enemy base. All by himself.
Not counting, of course, invading a military HQ on Earth and murdering his way to the Tyranical Overlord on the Krill Homeworld.
Organic Technology: The Krill have some organic tech, though most of it is still mechanical. Their ships are living beings that form a psychic bond with their pilots to improve performance, and Krill Parasites are powerful living armor that, despite their name, are completely harmless, and in fact boost the physical capabilities of their wearer.
Power-Up Letdown: One of the game's highlights is the vast array of options to customize your ship's guns. You'll find lots of these upgrades hidden all throughout the game as you progress through it. Only a small handful of them are actually worth the trouble to find.
Random Encounters: Whenever one of these occurs, you are beamed up to a spaceship, and fight enemies shmup-style until you shoot down a certain amount of them. Bonus points to the "random" aspect, as the ship you pilot is also random. Possibly the only justified use of this trope in video game history — the idea is that your parasite notices the ships getting nervous above, and beams you up to them if it thinks there are enemies.
Rapunzel Hair: Psyme, though it's only noticeable in a few shots (her parasite makes her look like she has short hair).
Single-Biome Planet: Used heavily, even in Earth's case (Earth is at one point referred to as the "Ocean Planet").
Slap-Slap-Kiss: Recker's relationship with Psyme is something of a volatile one. When he first meets her he blasts her out of the sky, and she spends most of the game calling him an idiot for not automatically knowing everything about her Bizarre Alien Biology. She threatens to kill Recker several times, and that's before she gets really pissed off at him.
Spam Attack: The best gun data combinations all tend to be these.
Turned Against Their Masters: The Iot were the original creators of the Sleeping Flesh. The Krill caught on early and removed a Sleeper from Earth, then used it to wipe out the Iot in retaliation for "impregnating" the Krill Homeworld with another Sleeper.
Twenty-Four-Hour Armor: The parasites hardly ever come off—according to some dialogue on the Ice Planet, some Krill don't even take them off to shower.
Twin Telepathy: Psyme's younger sisters Lolly, Folly, and Sliss are "tri-oplets": triplets that share a Psychic Link. They always operate and often speak in unison, leading the Krill to consider them as a single Hive Mind-like entity. They also count as The Dividual.
The Virus: A very significant portion of the game's plot centers around a mysterious, human-developed virus.
Welcome Back, Traitor: Inverted. You're allowed surprising free reign of the Krill's starbase network even after you've obviously expressed your intent to betray them (yet before you have a significant bargaining chip).
What Measure Is A Nonhuman: Admittedly, the humans have a reason to hate the Krill, but making boots from the skin of dead Krill pilots is probably overkill.